The present invention relates to a sewing machine in general, and more particularly to a synchronizing fabric feeding device for a sewing machine, wherein a movable fabric presser is provided in addition to the conventional fabric presser foot mounted on the lower end of a presser bar, the movable fabric presser being operated in synchronism with a feed dog to effectively and positively feed a fabric to be sewn with respect to a needle.
Generally, a sewing machine is used to sew two superposed fabrics to form up clothes or other articles. The superposed fabrics are stitched together with a machine needle while the superposed fabrics are transported with respect to the machine needle by a feed dog. As generally known, the feed dog is able to transport the fabric which is placed on the feed dog in cooperation with a fabric presser foot which is mounted on the lower end of a presser bar and presses the fabric against the feed dog with the predetermined force. In this case, it is apparent that the upper fabric lags behind the lower fabric due to the friction produced between the upper fabric and the presser foot pressed against the upper fabric. In fact, no practical problem arises when cotton or wollen fabrics and the like are stitched together which will produce little friction. However, a problem normally arises when a specific fabric such as artificial or vinyl leather and the like produces much friction in connection with the presser foot. In this case, the fabric will not be transported, or the upper fabric will lag behind the lower fabric which may be transported by the feed dog, and as a result the sewn fabrics will shrink because of puckering.
So far many devices such as an auxiliary presser foot have been provided to solve such problem, but these conventional devices are bulky and complicated in structure and also costly. Moreover, it is considerably difficult to attach or detach the auxiliary presser foot to and from the device in dependence upon the kind of fabric to be sewn. For these reasons, it has been difficult to actually reduce to practice such devices, especially for household sewing machines.